The Fsc-A line of Sprague-Dawley albino rats is characterized by hereditary clinical anophthalmia. This trait appears to be a simple Mendelian recessive and its expression ranges from the complete absence of an eye through microphthalmia in the adult. The initial manifestation of the defect occurs during the process of invagination of the optic vesicle and lens placode to form the optic cup and lens vesicle respectively. Recently, this trait has been transferred to Long-Evans Hooded rats which have pigmented eyes. The proposed study will involve carrying out the initial steps required for the establishment of a Fsc-P (pigmented) inbred line of rats which carry this trait. Additional breeding of the Fsc-A line will be carried out in order to continue the inbreeding process which is now at the 7th generation. Out- breeding studies will be conducted in the Fsc-P line to determine the genetic characteristics of the trait as it is expressed in pigmented animals. Analysis of the morphological, cytological and histochemical changes which occur in embryos from both of these lines during the period of invagination of the optic vesicle and lens placode will be carried out using three dimensional reconstruction techniques, differential staining and scanning electron microscopy.